Ultraviolet absorbing layers



Oct. 12, 1954 s. s. FIERKE 2,691,579

ULTRAVIOLET ABSORBING LAYERS Filed Oct. 51, 1952 FILTER LAYER coxvmwl/ve 3,3- D/ETHYL TH/A cm/w/vfi CHAOR/DE ,4/1/0 STYREA/f- MALEAM/C ACID RES/IV EMULSION $cew-inflmerke I N V EN TOR.

ATTY & A6122 Patented Oct. 12, 1954 UNI TE STATES FAYENE ULTRAVIOLET ABSORBING LAYERS Application October 31, 1952, Serial No. 317,896

Claims.

This invention relates to new photographic elements protected against the harmful effects of ultraviolet radiation.

It is known that certain materials, such as cellulosic films and photographic layers, are adversely affected by ultraviolet radiation when such materials are exposed to daylight. In the case of photographic layers, the ultraviolet radiation sometimes causes undesired exposure of the layer, or layers, since photographic silver halide emulsions are sensitive to blue, violet and ultraviolet regions of the spectrum, in addition to any other sensitivity which may be given them, and in the exposure of such material, it is frequently desirable to prevent the action of ultraviolet light on the sensitiveemulsion. This is especially true in the case of photographic materials designed for use in color photography where the film has been sensitized to the longer wavelength regions where it is desirable to record only the rays of the visible spectrum.

Color photographs on multilayer photographic material, particularly where the dye images are formed in sensitive emulsion layers by color development, are susceptible to fading and discoloration by the action of ultraviolet radiation to which the photographs are subjected during viewing. It is also known that the residual couplers contained in the emulsion layers after formation of the picture images in certain processes, are attacked by ultraviolet radiation and form a stain which is undesirable in the finished photograph. The action of ultraviolet radiation on finished color photographs is particularly noticeable in positive prints on paper or other opaque supports, since this type of print is frequently'viewed in daylight where there is a high content of ultraviolet radiation; This dye fading and yellowing appears to be caused primarily by those wavelengths of light which lie close to the visual region of the spectrum, i. e. 360-400 millimicrons.

I have now found that certain cyanine dyes are useful in absorbing harmful ultraviolet radiation when such dyes are incorporated in a gelatin layer containing a certain type of synthetic resin which acts as a mordant for the cyanine dye.

It is, therefore, an object of my invention to provide new photographic elements protected against the harmful effects of ultraviolet radiation. A further object is to provide photographic color materials Which have been protected against the harmful effects of ultraviolet radiation. Other objects will become apparent from a consideration of the following description and examples.

The accompanying drawing illustrates schematically a cross-sectional View of a sensitive photographic element having an ultraviolet filter layer containing a synthetic resin which acts as a mordant for the ultraviolet absorbing compounds used according to my invention. Advantageously, the ultraviolet absorbing compound is incorporated in the photographic element by bathing the photographic element, which contains a gelatin layer having incorporated therein one of the synthetic resins mentioned above, in an aqueous solution of the ultraviolet absorbing compound. Alternatively, the ultraviolet absorbing compound, which in this case is a particular type of cyan ne dye, can be incorporated directly in the gelatin layer before or during coating. Instead of using gelatin as the binder, other water-permeable, hydrophylic colloids can be used, such as synthetic resins (e. g. polyvinyl acetals, hydrolyzed polyvinyl acetate, etc.), hydrolyzed cellulose esters, etc.

Where the photographic element is a material intended for use in color photography, the ultraviolet filter need not be an outer layer, but this layer can be placed over one of the layers subject to the harmful effects of ultraviolet radiation. For example, in a multilayer material comprising three differentially sensitized layers, the red sensitive layer being adjacent to the support, the green sensitive layer being superposed on the red sensitive layer, and the blue sensitive layer being outermost with respect to the other light-sensitive layers, the ultraviolet filter layer can be placed between the blue and green sensitive layers. Alternatively, the ultraviolet filter layer can be placed between the green and red sensitive layers. The amount of ultraviolet absorbing compound can be varied, depending upon the effect desired and the use to which the material is to be put.

The particular ultraviolet absorbing compounds useful in practicing my invention can advantageously be represented by the following two general formulas:

butyl, carboxymethyl, carbethoxymethyl, nlauryl, benzyl (phenylmethyl), etc., R2 and R3 each represents an alkyl group, such as methyl, ethyl, n-propyl, etc., R4 represents an alkyl group containing at least 9 carbon atoms, such as nnonyl, n-decyl, n-lauryl, n-cetyl, etc., X represents an acid radical, such as chloride, bromide, iodide, perchlorate, p-toluenesulfonate, benzenesulfonate, etc., and Z and Z1 each represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of those of the benzothiazole series, such as benzothiazole, 4-chlorobenzdthiazole, 5-chlorobenzothiazole, 5-methylbe'nzothiazole, 5-p'henylbenzothiazole, 6 methoxybenzothiazole, etc., those of the benzoxazole series, such as benzoxazole, 5-chlorobenzoxazole, 5-phenylbenzoxazole, 5-methoxybenzoxazole, etc., those of the thiazoline series, such as thiazoline, l-phenylthiaz- 'oline, 5-methylthiazoline, etc., and those of the thiazole series, such as thiazole, 4,5-diphenyla thiazole, 4-phenylthiazole, 5-phenylthiazole, etc.

The dyes represented by Formula I above can advantageously be prepared according to the methods described in U. S. Patent 2,108,485 or British Patent 423,792, or other methods known in the art. Also the dyes of Formula I can be prepared according to the method described in Jones et a1. U. S. application Serial No. 291,802, filed June 4, 1952. The cyanine dyes of Formula '11 above can be prepared according to the method described in British Patent 529,440, for example.

Typical dyes which can be employed in my inventioncomprise those represented by the following formulas:

3-ethyl-3-n-lauryloxathiazolinocyanine iodide C 2H6 C 1 C 2H5 3 ,3 -diethyl-5 ,5 -diphenyloxacyanine chloride CE: I

OOH 3-carboxymethy1-3'-ethylthiacyanine iodide 3,3-diethylthiacyanine p-toluene'sulfonate 3,3-diethyloxacyanine chloride "of the solution was 5.

BQ MII) [1-n-no11y1-2,5-dimethylpyrrole (3)] [S-ethylbenzoxazole (2) dimethinecyanine chloride [l-n-cetyl-2,5-dimethylpyrrole (3) [3-ethylbenzoxazole (2) ]dimethi11ecyanine iodide [l-nJaur-yl-Z, 5 dimethylpyrrole (3)] [3-ethylbenzo'thiazole (2) dimethinecyanine chloride Synthetic resins which can be employed as mordants for the above dyes comprise 'interp'o'lymers of styrene'with'male'amic 'acids, is. g. Amberlite W-1. These latter resins have been previously described in U. 'S. Patent 2,3l3,565 and Godowsky U. S. Serial 'No. 156,066, filed April 15,1950. The process 'of 'rnaking su'ich 'resin's comprises reacting a styrene-maleic anhy'dri'd'e resin with ammonia'or an amine, s'u'ch'as aniline, nbutylamine, n-amyla'rnine, etc. Alternatively, such resins can be prepared 'by hydrolysis (partial or complete) of interpolymers of styrene with maleinimide. I

The advantages of my invention have been found to 'be particularly useful with respect -to the use of the dyes repre'sented'by'the 'abovegeneral formulas, and it has been found that other similar dyes do not provide the useful results 'obtained with the particular dyes army invention; for example, such dyes as 4-[(3-eth'y'l-2(3H)- benzoxazolylidene)ethylidene] -'3 methyl 1 phenyl-5-pyrazo1one and '2-lfi-(l-pip'eridyl) tinyllbenzothiazole methiodide are not retained in gelatin layers during the washing operations to which such layers are customarily subjected. This is true even though substantial amounts of synthetic resin are present in the gelatin or colloidal binder.

The following examples will serve to illustrate more fully the manner whereby I practice my invention.

EXAMPLE 1 -Amberlite W-l was mixed with a-gelatin solution and the mixture coatediritoa thin -film=containingabout 50 m'gJper square-foot of theAm- 'berlite. The coating was then-dried andsoaked in a 1% aqueous solution of 3,3diethyloxacyanine chloride for 10 minutes at'68" F. The pI-I The coating was then washed running "water for 5 minutes, dried, mounted anda spectrophotomet'ric measurement made which showed that the coatin'g absorbed substantially 'all radiation between 360 and 400 'millimicrons, but transmitted substantially "all radiation of wavelengths greater than '400-mil1imicrons.

EXAMPLE 2 A coating was made in substantially the same manner as that described in Example 1 above, except that styrene-maleamic acid resin obtained according to U. S. Patent 2,313,565 was employed instead of the Amberlite. The coating absorbed substantially all radiation between 360 and 4.00 millimicrons but transmitted substantially all radiation of wavelength greater than 400 millimicrons.

EXAMPLE 3 A series of cyanine dyes were adsorbed onto a coating containing only gelatin, and the same cyanine dyes were adsorbed onto a second coating containing styrene-maleamic acid resin plus gelatin. The following procedure was used:

0.1 g. of the cyanine dye was dissolved in 50 cc. of ethyl alcohol and then 50 cc. of water was added to the solution. The dyes remained in solution, and the two coatings were immersed in the solution for 5 minutes, then washed for 20 minutes in running water and dried. Density and wavelength of absorption were obtained to evaluate the retention characteristics of the dyes. The following results were noted.

a. 3 ethyl 3' n Zauryloscathiazolinlocyanine iodide.-This dye had an absorption maximum at 350 millimicrons and showed a density of 3.3 with the coating containing the resin, while the density of the coating with the gelatin alone was only 0.87, indicated preferential adsorption.

b. 3,3 diethyl 5,5 diphenylozcacyanine chZorz'de.This compound had a maximum absorption at 376-405 millimicrons and showed a density above 4 with respect to the coating containing the styrene-maleamic acid resin, although the density was only 1.5 with respect to the coating containing only gelatin.

0. [1 n cetyl 2,5 dimethylpyrrole (3) 1 [3 ethylbenzoxazole (2)]dimethz'necyanine chloride.--This compound showed excellent adsorption to the coating containing the styrene-maleamic acid resin, having a density of 2.88 as contrasted to a density of 0.84 for the coating containing the gelatin alone. Maximum absorption occurred at about 4.40 millimicrons.

d. 3 carbomymethyl 3' ethylthiacyam'ne iodide.-This dye was adsorbed tightly to the coating containing the styrene-maleamic acid resin, showing a density of 3.3 as contrasted to a density of 0.18 for the gelatin coating. Maximum absorption occurred at 400 millimicrons.

e. 3,3 diethylthiacyamne p toluenesulfonate.This compound had maximum absorption at 400 millimicrons and was adsorbed to the coating containing the styrene-maleamic acid resin to give a density of 2.86, while the density of the coating containing only the gelatin was 0.1.

The coatings employed in Examples 1 and 2 respectively were two strips which had been developed in a complete color process. The coatings, after subjection to daylight for a substantial period of time, showed little change, insofar as fading or print-out were concerned.

The support employed in the photographic elements of my invention can be either transparent, such as cellulose acetate, cellulose nitrate, etc., or opaque, such as paper, metal, etc.

The accompanying drawing illustrates schematically a cross-sectional view of a photographic element containing a layer having incorporated therein 3,3-diethylthiacyanine p-toluenesulfonate and a styrene-maleamic acid resin. As shown in the single figure of the drawing, a support In of anysuitable material, such as cellulose acetate or paper, for example, having thereon a light-sensitive photographic silver halide emulsion layer II is coated with a filter layer [2 of gelatin having incorporated therein 3,3'-diethylthiacyanine p-toluenesulfonate and a styrenemaleamic acid resin. The filter layer 12 serves to protect the photographic element from the harmful efiects of ultraviolet radiation both during exposure and after completion of photographic processes. It will be understood that the drawing is merely representative of other structures which can be employed in my invention, and that the element can have other layers, not shown, such as additional light-sensitive layers, subbing layers, antihalation layers, etc.

As noted above, the styrene-maleamic resins used in my invention have been previously described in the prior art. Such resins can be designated as having a polymeric hydrocarbon chain having substituted thereon at recurring intervals phenyl groups and carboxyl groups, together with carbonamide and/or carboxylic imide groups. Similar useful resins having such structure can be obtained from styrene-acrylic acid, styrenemethacrylic acid, or styrene-itaconic acid interpolymers (instead of from styrene-maleic anhydride polymers as is described above).

The following two examples will serve to illustrate the manner whereby resins useful in practicing my invention can be prepared.

EXAMPLE A PoZystyrene-maleamic acid polymer 50 gm. of polystyrenemaleic anhydride were added gradually to 250 ml. of 28% ammonium hydroxide in a 500 ml. Erlenmeyer flask with stirring from a mixer to form a slurry. After stirring for eighteen hours at room temperature a viscous, clear colorless dope was obtained. 300 gm. of this dope was diluted to approximately 2% solids with water and 48% hydrobromic acid was added to it until it was just acid to Congo Red. The solid that was formed was separated by filtration, and leached with absolute alcohol until the wash solutions were bromide free. The solids were put to dry in an oven at 60 C.

20 gm. of the solid were doped to form a 5% dope by weight in water made alkaline with 13 ml. of 20% sodium hydroxide. pH=8.63.

EXAMPLE B PoZystyrene-maleamic acid ammonium salt The following reagents were put to reflux in an all glass reflux outfit equipped with a mechanical stirrer. Conditions were maintained anhydrous by calcium chloride tubes on all openings to the atmosphere.

49 gm. maleic anhydride (Eastman white label) 52 gm. distilled styrene 1500 ml. dry toluene 2.0 gm. benzoyl peroxide The reaction mixture was heated for 2% hours on a steam bath without stirring and then allowed to cool to room temperature. A small sample of the solids was withdrawn, washed with fresh benzene, and put to dry for analysis and viscosity purposes.

The sitrrer was turned on and dry ammonia was bubbled into the reaction mixture continuously for 3 /2 hours. During this time the temperature within the reaction mixture rose from a starting temperature of 23 C. to 45 C, and

then returned to 23 C. The solids were 'filtered off on a' Buchner funnel, washed with toluene, and :put to dry in a vacuum 'oven at 60 C. overnight.

The residual toluene was then extracted with absolute "alcohol by stirring the product with 2-3 liter portions of absolute ethyl alcohol and filtering onto a Buchner funnel. The product was then dried-as'above.

Forty grams of the polymer were gradually -added to 200 m1. of water in an Erlenmeyer flask with mechanical stirring. The solution was kept slightly alkaline by the portion-wise addition of 28% NH4OII, The pH was neverallowed to exceedeight. A-cle'ar colorless dope was obtained which was then adjusted to solids by weight by the addition of distilled water. The pH of this 'solution was 6.38.

What I claim as my invention and desire secured by Letters Patent of the United States is:

l. A photographic element comprising a sup- .port, a' photographic gelatino-silver halide emulsion layer, and a gelatin layer containing (1') an interpolymer of styrene and an unsaturated, aliphatic carboxylic compound, said interpolymer having a polymeric hydrocarbon chain having substituted at recurring intervals phenyl groups and carboxylic :groups, together with groups selected from the group consisting of carbonamide and 'carboxylic imidegroups, and (2) an ultraviolet absorbing compound selected from those represented by the following two general formulas:

wherein R, R1, R2, and R3 each "represents an alkyl group, R4 represents an alkyl group containing at least nine carbon atomsQX represents an acid radical, and Z and Z1-each represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected "from those of the benzoxazole series, those of the thiazoline series, those of the thiazole series, and those of the benzothiazole series.

2. A photographic element comprising a supiport, :a photographic .ge'latino-silver halide emulsion layer, and a gelatin layersuperposedonsaid iphotograp'hic gelatino-silver halide emulsion, said gelatin layer containing (1) an interpolymer of styrene and a maleamic acid, and (2) an ultraviolet absorbing compound selected from those represented by the following general formula:

,Z\ t R1 b-on=o wherein-Rand R1 each represents an alkylgroup, X'represents'an acid radicaL-andZ and'Z1 each represents the non-metallic -atoms necessary to complete a heterocyclic nucleus selected from the group consisting of those of the benaoxazole "series, those of the thiazoline series, thoseofthe thiazole series, and those of the 'benzothiazole s'erics.

3AA photographic element-comprising a supwherein R, R2, and R3 each represents an alkyl group, R4 represents an alkyl group containing at least nine carbon atoms, X represents an acid radical, and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of those of the benzoxazole series, those of the thiazoline series, those of the thiazole series, and those of the benzothiazole series.

4. A finished photographic element comprising a-support having thereon a plurality of developed and fixed photographic emulsion layers containing coupled-dye images, at least one of said dye images being subject to fading by the action of ultraviolet radiation, said emulsion layer containing a coupled-dye image subject to fading lying between said support and a gelatin layer containing (1) an interploymer of styrene and a maleamicacid and (2) an ultraviolet absorbing compound selected from those represented by the wherein R, R1, R2, and R3 each represents an alkyl group, R4 represents an alkyl group containing at least nine carbon atoms, X represents anacid radicaLand Z and Z1 each represents the non-metallic atoms necessary to complete a 'heterocyclic nucleus selected from the group consisting of those of the benaoxazole series, those of the thiazoline series, those of the thiazole seriesand those of the benzothiazole series.

5. A photographic element according to claim l wherein the support is a paper support.

6. A photographic element comprising a support, a photographic gelatino-silver halide emulsion'layer, and a gelatin layer containing (1) an interpolymer of styrene and a maleamic acid and 2) an ultraviolet absorbing compound having the followingformula:

C2435 \CI (IJ2H5 said photographic gelatino-silver halideemulsion layer lying between said support and said gelatin layer.

'7. A photographic element comprising a sup- HiCr- "port, a photographic gelatino-silver halide emulsion layer, and a gelatin layer containing (1) an interpolymer of styrene and a maleamic acid and (2) an ultraviolet absorbing compound having the following formula:

said photographic gelatino-silver halide emulsion layer lying between said support and said gelatin layer.

9. A photographic element comprising a support, a photographic gelatino-silver halide emulsion layer, and a gelatin layer containing (1) an 5 interpolymer'of styrene and a maleamic acid and .10 (2) an ultraviolet absorbing compound having the following formula:

N/ \N Ca I CBHB O OH said photographic gelatino-silver halide emulsion layer lying between said support and said gelatin layer.

10. A photographic element comprising a support, a photographic gelatino-silver halide emulsion layer, and a gelatin layer containing (1) an interpolymer of styrene and a maleamic acid and (2) an ultraviolet absorbing compound having the following formula:

- N N l I said photographic gelatino-silver halide emulsion layer lying between said support and said gelatin layer.

References Cited in the file of this patent UNITED STATES PATENTS Name Date Richardson June 6, 1939 Number 

1. A PHOTOGRAPHIC ELEMENT COMPRISING A SUPPORT, A PHOTOGRAPHIC GELATION-SILVER HALIDE EMULSION LAYER, AND A GELATIN LAYER CONTAINING (1) AN INTERPOLYMER OF STYRENE AND AN UNSATURATED, ALIPHATIC CARBOXYLIC COMPOUND, SAID INTERPOLYMER HAVING A POLYMERIC HYDROCARBON CHAIN HAVING SUBSTITUTED AT RECURRING INTERVALS PHENYL GROUPS AND CARBOXYLIC GROUPS, TOGETHER WITH GROUPS SELECTED FROM THE GROUP CONSISTING OF CARBONAMIDE AND CARBOXYLIC IMIDE GROUPS, AND (2) AN ULTRAVIOLET ABSORBING COMPOUND SELECTED FROM THOSE REPRESENTED BY THE FOLLOWING TWO GENERAL FORMULAS: 